The sale will only last until March 20th, so if you're planning to grab Total War: Warhammer or any of its DLC make sure to do it as soon as possible, lest you forget. As for whether any of it is worth your time and money, that I cannot answer for you, but I can give you my opinion in the shape of review I did a little while back. If you're just interested in the short version, however, here it is:

"Total War: Warhammer is a crossover between two franchises I've enjoyed for many years now, and I'm delighted to say that it manages to be faithful to both sides. But perhaps most importantly, it manages to be an actually enjoyable experience on its own. It has some obvious flaws, especially when it comes to the generic campaign ending, terrible diplomacy system, and occasional performance woes, but even with all of that considered this is the most fun I've had with a Total War game."

If you decide to buy the base game just make sure you don't forget to download all of the free DLC as well. For some reason none of it is included in the main download, so you will have to go to each one's Steam Store page in order to grab them one by one. Its stupid and convoluted, but the DLC is well worth the trouble. Have fun!